British investigators have determined that a 2014 runway excursion at London Biggin Hill Airport (EGKB) was the result of the flight crew lining up their U.S.-registered Gulfstream III (N103CD) with runway edge lighting, mistakenly believing them to mark the runway centerline, before attempting to depart for Gander, Newfoundland. The aircraft was substantially damaged, but the two pilots and five passengers were not injured.
According to the recently issued report by the UK Air Accidents Investigation Branch (AAIB), recorded weather at the time of the Nov. 24, 2014 accident indicated 10 miles visibility and calm wind, with a close temperature/dew point spread and intermittent patches of thick ground fog.
As the aircraft taxied out for departure at 8:30 p.m., ATC issued an advisory for patches of fog throughout the airport, including “very low, very thin fog from the zero three threshold to approximately halfway down the runway.” The pilots acknowledged this transmission, and later told investigators they had noticed a “glow” around the runway lights, although they did not believe conditions posed a hazard.
Runway 3 lacked centerline lighting and was not approved for takeoffs with a runway visual range (RVR) of less than 400 meters. Investigators also noted that the crew was “used to making their own judgments as to whether the visibility was suitable for a takeoff” under U.S. FAR Part 91.
“Information available to the pilots allowed them to develop an incorrect mental model of their route from the holding point to the runway,” the report noted. “Environmental cues indicating that the aircraft was in the wrong position for takeoff were not strong enough to alert the pilots to the fact that they had lost situational awareness.”
A paved staging area and taxiway along the right side of the departure threshold allowed the jet to travel 814 feet on hard surface before rolling into grass, at which time the crew rejected the takeoff. The AAIB noted this pavement configuration may have also contributed to the crew’s confusion and issued Safety Recommendation 2015-038 advising ICAO to develop a global standard to better differentiate runway edge lights from other airfield lighting.